Abstract: A circuit arrangement for clock pulse recovery on the receiving side of a digital clock-controlled data system is particularly characterized in that in the receiver a branch circuit is connected to the input side in parallel with a digital converter for converting the digital data signal, the branch circuit comprising an EXCLUSIVE or gate having two inputs and a delay element in the feed to one input of a digital counter which is connected to the output of the EXCLUSIVE OR gate and actuated by a quartz-stabilized oscillator having a frequency of multiple of the desired timing frequency and whose output is connected to the digital converter.

Abstract: A radio system for communications transmission between transmitting/receiving stations moving along prescribed routes and stationary transmitting/receiving stations arranged along these routes at prescribed intervals and effective in both route directions, provides that the stationary stations of one route are connected by way of cable to a central transmitting/receiving station. A carrier signal generator is connected to that end of the cable which is farthest from the central transmitting/receiving station and an amplitude modulator is connected parallel at the locations along the cable provided for the input of signals and formed by the stationary transmitting/receiving stations, and are respectively connected by way of a transformer having a high transmission ratio. A demodulator having a threshold value circuit is inserted in the central transmitting/receiving station at the end of the cable. The radio system is of particular advantage in railway radio.

Abstract: A duplex microwave radio communication and telemetry system for transmitting analog and digital data between fixed stations as well as to mobile stations wherein the microwave oscillator is stabilized by utilizing a free running oscillator which is controlled in frequency with the incoming modulation input and the output of the free running oscillator is supplied to a phase comparator and to a multiplier and the multiplier supplies an output to a mixer which also receives a portion of the input from the microwave oscillator and supplies an input to the phase comparator to provide a control signal for controlling the frequency of the microwave oscillator.

Abstract: A duplex-transmitter-receiver arrangement wherein only a single oscillator is utilized for the transmitter and receiver for a digitally modulated radio communication system wherein each location has a transmitter and receiver and a single oscillator is used for both the transmitter and receiver with a circulator switch connected respectively to the antenna, the receiver and the transmitter with the oscillator in the transmitter coupling through to the branch for the receiver so as to serve as a mixing frequency for the receiver.

Abstract: In one illustrated embodiment involving a railway communication system, about ten send-receive stations form a transmission section operating at one pair of frequencies in the range above one gigahertz, the stations being arranged at about one kilometer intervals along the route for radio communication with mobile stations moving therealong. A next succeeding similar transmission section operates at a different pair of send and receive frequencies above one gigahertz. All of the stations of a given transmission section may be in communication with a main station by means of a parallel cable connection. A central station then may communicate with mobile stations via the respective main stations. In another embodiment, the stations are implemented as microwave relay stations linked to a main station by the same antenna system used for communication with the mobile stations.